1. Field of the Invention
The present invention relates to self-cleaning compositions and a process for preventing and reducing surface stain accumulation due to bird droppings, bug wastes, food debris, and other stain causing materials.
2. Technical Background
Both interior and exterior surfaces of automobile, such as coatings, paints, and seat fabrics, are subject to contamination and corrosions when they are under prolonged exposure to bird dropping, insect debris, resins of conifer, microbes, gums, etc. Certain stains, such as insect-originated stains, are hard to remove with regular automatic brush-free washing. Interior surfaces and coatings may also be easily get stained with oil, protein, sugar and other ingredients in foods and beverages, and timely removal of such stains may present certain challenges.
Here, the present invention specifically involves the incorporation of digestive proteins including lysozymes, proteases, lipases, cellulases, etc., onto surfaces such as paints and coatings. The catalytic activity of the digestive proteins enables ongoing self-cleaning to reduce and eliminate stain contaminations. The mechanism of action of these digestive proteins is mainly enzymatic in nature and does not involve the use of any corrosive or oxidative components; therefore, they are environmentally friendly.
Stains of interests in the initial stage of this work include those formed from broken bodies of bugs, animal (like bird) wastes, foods, milk and other beverages, and cosmetic and personal care products. Although the detailed components vary with sources of stains, the major components of stains that are adhesive to surfaces are proteins, polysaccharides, fats or oils.
3. Description of Related Art
It is known to incorporate enzymes into coating or into substrates for the purpose of providing a surface with antimicrobial, antifungal or antifouling properties. Yet it is novel to the best knowledge of Applicants to attach digestive proteins to a surface for the purpose of enzymatically decomposing stain molecules in contact with the surface.
U.S. Pat. No. 6,818,212 discloses an enzymatic antimicrobial ingredient for disinfection and for killing microbial cells.
Wang et al. 2001 discloses lifespan extension of an enzyme upon its covalent binding at wet conditions; yet the reference does not seem to mention the utilization of such covalently bound enzyme in the area of surface self-cleaning.
U.S. Pat. No. 3,705,398 discloses polymeric articles having active antibacterial, antifungal and combinations of antibacterial and antifungal properties. The antibacterial and antifungal activating agents are distributed within the polymeric composition and migrate to the surface.
U.S. Pat. No. 5,914,367 discloses a method of preparing a polymer-protein composite including polymerizing a monomer in the presence of a protein dissolved in an organic phase via the ion-pairing of the protein with a surfactant. This reference, however, does not seem to mention the prevention or reduction of stain accumulation using the digestive power of such a polymer-protein composite.
U.S. Pat. No. 6,150,146 discloses a method of releasing a compound having antimicrobial activity from a matrix at a controlled rate. The method includes an enzyme and a substrate within the matrix beforehand to allow the enzyme and substrate to react with each other in the matrix, thereby to produce a compound having antimicrobial activity. The patent also discloses a coating composition comprising a film-forming resin, an enzyme, a substrate and any enzyme capable of reacting with the substrate.
U.S. 2005/0058689 discloses paints and coatings having antifungal growth and antibacterial materials. Specific chemicals and formations are disclosed for incorporation into painted surfaces which are antifungal compositions to inhibit growth of mold, bacterial, and fungi on building materials.
The object of the present invention is to provide self-cleaning composition and process containing digestive proteins for preventing and reducing stain accumulation.